Hemilecanium Newstead, 1906

Hodgson, Chris, 2008, A new genus and two new species of soft scale insect (Sternorrhyncha, Coccoidea, Coccidae) from Africa, ZooKeys 3 (3), pp. 57-76 : 62-63

Hemilecanium Newstead

urn:lsid:zoobank.org:author:2DEA755F-A46A-4203-B3B8-893324D22FAF

urn:lsid:zoobank.org:pub:7FB67D8F-AAA7-427B-AF54-53D64A52B87A

The genus Hemilecanium was introduced by Newstead (1908) to take H. theobromae , collected off cacao in Cameroon. Prior to 2005, Hemilecanium contained 4 species: H. coriaceum Hall , H. imbricans (Green) , H. recurvatum Newstead and the type species. Since then however, there have been major changes in the species composition of Hemilecanium , most notably when Kondo and Hardy recently (2008) synonymised Etiennea Matile-Ferrero (type species E. villiersi Matile-Ferrero ) with Hemilecanium , based on a comparative morphological study of the adult females, adult males and 1 st- instar nymphs of 4 species of Hemilecanium and 6 species of Etiennea . The study also included a phylogenetic analysis based on adult female and 1 st- instar nymphal characters. These changes brought the total number of species in Hemilecanium to 26. Earlier, Hodgson (1994) had drawn attention to the morphological similarities of Etiennea and Hemilecanium (both genera having dorsal tubular ducts with funnel-like apertures and both with two centres of sclerotisation on the dorsum) but had considered that they could be easily separated due to the presence of cribriform plates on Hemilecanium (absent on Etiennea species). However, Kondo and Williams (2005) showed that 4 cribriform plates were present on the dorsum of the 1 st- instar nymphs of several Hemilecanium species so that the 1 st- instar nymphs of E. villiersi and H. theobromae were very similar.

Despite these changes, the species within the new concept of Hemilecanium can be divided into two groups based on the structure of the 1 st- instar nymphs. These are referred to as the petasus and thoebromae groups by Kondo and Hardy (2008). The 1 st- instar nymphs are only known for nine of the species now included in Hemilecanium but these can be separated as follows: the petasus group is diagnosed by the presence of: (i) the dorsum without clusters of 4-locular pores; (ii) each spiracular pore band with 2-4 spiracular disc-pores; (iii) each femur with a very long seta near apex (only on the prothoracic leg of H. uesatoi ), and (iv) each stigmatic cleft with 3 well-developed stigmatic spines. The petasus group includes H. ferox (Newstead) , H. montricardiae (Newstead) , H. multituberculatum (Hodgson) , H. petasus (Hodgson) , H. sinetuberculum (Hodgson) and H. uesatoi Kondo & Hardy. The theobromae group, on the other hand, has the following combination of characters: (i) dorsum with 4 clusters of 4-locular pores; (ii) each spiracular pore band with 1 spiracular disc-pore; (iii) very long setae absent from all femora, and (iv) stigmatic spines absent. It includes H. imbricans , H. mangiferae Kondo & Williams , H. theobromae and H. villiersi . As pointed out by Kondo and Hardy, these two groups are also supported by a single adult female character, with those in the theobromae group lacking stigmatic spines while those in the petasus group have well-developed stigmatic spines. This suggests that the present composition of Hemilecanium may be paraphyletic. This was understood by Kondo and Hardy who go on to say (2008, p. 212) “We need data on first-instar nymphs of additional species to determine whether these two crawler types and their associated adult females will correspond to reciprocally monophyletic groups”.

Below is described a further species which is here being tentatively placed in Hemilecanium . Although the 1 st- instar nymphs fulfil the 4 character-states for the petasus group discussed above, they also have an apparently unique character – 1-4 coneshaped or flap-like triangular structures medially on most segments.